diff --git a/aiogram/types/chat_action.py b/aiogram/types/chat_action.py
index 0fbd64da..f0b46614 100644
--- a/aiogram/types/chat_action.py
+++ b/aiogram/types/chat_action.py
@@ -20,16 +20,16 @@ class ChatAction(AutoName):
     Source: https://core.telegram.org/bots/api#sendchataction
     """
 
-    TYPING: str = enum.auto()
-    UPLOAD_PHOTO: str = enum.auto()
-    RECORD_VIDEO: str = enum.auto()
-    UPLOAD_VIDEO: str = enum.auto()
-    RECORD_AUDIO: str = enum.auto()
-    UPLOAD_AUDIO: str = enum.auto()
-    RECORD_VOICE: str = enum.auto()
-    UPLOAD_VOICE: str = enum.auto()
-    UPLOAD_DOCUMENT: str = enum.auto()
-    FIND_LOCATION: str = enum.auto()
-    RECORD_VIDEO_NOTE: str = enum.auto()
-    UPLOAD_VIDEO_NOTE: str = enum.auto()
-    CHOOSE_STICKER: str = enum.auto()
+    TYPING = enum.auto()
+    UPLOAD_PHOTO = enum.auto()
+    RECORD_VIDEO = enum.auto()
+    UPLOAD_VIDEO = enum.auto()
+    UPLOAD_AUDIO = enum.auto()
+    RECORD_AUDIO = enum.auto()
+    RECORD_VOICE = enum.auto()
+    UPLOAD_VOICE = enum.auto()
+    UPLOAD_DOCUMENT = enum.auto()
+    FIND_LOCATION = enum.auto()
+    RECORD_VIDEO_NOTE = enum.auto()
+    UPLOAD_VIDEO_NOTE = enum.auto()
+    CHOOSE_STICKER = enum.auto()
diff --git a/aiogram/utils/enum.py b/aiogram/utils/enum.py
index 9e14795a..b239ebc0 100644
--- a/aiogram/utils/enum.py
+++ b/aiogram/utils/enum.py
@@ -1,7 +1,8 @@
 import enum
+from typing import Any, List
 
 
 class AutoName(str, enum.Enum):
-
-    def _generate_next_value_(self, start, count, last_values) -> str:
-        return self.lower()
+    @staticmethod
+    def _generate_next_value_(name: str, start: int, count: int, last_values: List[Any]) -> str:
+        return name.lower()